The present invention relates to processes and apparatuses for forming molded multi-layer golf balls. The molding apparatuses and processes include the use of a mandrel with a spherical portion sized to fit within a molding chamber. The present invention also relates to processes and apparatuses for forming golf ball cover layer(s) independently of golf ball cores or intermediate ball assemblies, applying the cover layer(s) to a core or ball assembly, and then further molding to eliminate seams or other surface defects. The various processes and apparatuses described herein are also particularly well suited for use in conjunction with reaction injection molding techniques.
A number of two-piece (a solid resilient center or core with a molded cover) and multi-layer (liquid or solid center and multiple mantle and/or cover layers) golf balls have been produced. Different types of materials and/or processing parameters have been utilized to formulate the cores, covers, etc. of these balls which dramatically alter the balls"" overall characteristics. In addition, multi-layer covers of different materials have also been formulated in an attempt to produce a golf ball having the overall distance, playability and durability characteristics desired.
For certain applications it is desirable to produce a golf ball having a very thin cover layer. However, due to equipment limitations, it is often very difficult to mold a thin cover. Accordingly, it would be beneficial to provide an apparatus and technique for producing a relatively thin outer cover layer.
Moreover, retractable pins have been utilized to hold, or center, the core or core and mantle and/or cover layer(s) in place while molding an outer cover layer thereon. The pins sometimes produce centering difficulties and cosmetic problems (i.e. pin flash, pin marks, etc.) during retraction, which in turn require additional handling to produce a golf ball suitable for use and sale. Additionally, the lower the viscosity of the mantle and/or cover materials, the greater the tendency for the retractable pins to stick due to material accumulation, making it necessary to shut down and clean the molds routinely. Accordingly, it would be desirable to provide an apparatus and method for forming a cover layer on a golf ball without the use of retractable pins.
One aspect of the present invention is to provide equipment and methods for forming a golf ball with a cover that has a favorable combination of playability properties yet which may be manufactured more cost effectively and without many of the problems associated with prior balls.
A further aspect of the invention is to provide equipment and methods for forming a golf ball having a dimpled cover that is thinner than traditional cover layers.
Another aspect of the invention is to provide novel molding equipment that simplifies manufacturing of golf balls and components thereof.
The molding equipment includes the use of a mandrel with a spherical portion sized to fit within a molding chamber.
In a further aspect, the present invention provides a molding apparatus comprising a first mold having a generally flat first mating surface and a first hemispherical molding surface. The first mold defines at least one passage extending between the first molding surface and the exterior of the mold. The molding apparatus also comprises a second mold having a generally flat second mating surface and a second hemispherical molding surface. The second mold defines at least one passage extending between the second molding surface and the exterior of the second mold. Upon placing the apparatus in the molding configuration, the first and second mating surfaces generally contact one another, so that the first and second molding surfaces form a generally spherical molding chamber. The at least one passage defined in each of the first and second molds is aligned with each other. The molding apparatus also comprises a mandrel having a spherical portion sized to fit within the spherical molding chamber formed by the apparatus when the apparatus is placed in a molding configuration. The mandrel also has at least one member extending from the spherical portion and sized to fit within the at least one passage defined in each of the first and second molds.
In another aspect, the present invention provides a process for forming portions of a golf ball cover. The process comprises providing a molding assembly including a first mold defining a first hemispherical molding surface and at least one passage extending between the first molding surface and an exterior of the first mold. The first mold also defines a first mating surface. The molding assembly additionally includes a second mold defining a second hemispherical molding surface and at least one passage extending between the second molding surface and an exterior of the second mold. The second mold also defines a second mating surface. The molding assembly further includes a mandrel having a generally spherical portion sized to fit within the first and second hemispherical molding surfaces and which creates a void between an outer surface of the spherical portion and the first and second hemispherical molding surfaces. The mandrel also has a member extending from the spherical portion. The process includes a step of positioning the mandrel between the first mold and the second mold such that the spherical portion of the mandrel is generally disposed in the first and second hemispherical molding surfaces. The process includes another step of providing a flowable molding material. The process further includes a step of introducing the material into a void defined between the outer surface of the spherical portion and the first and second hemispherical molding surfaces. The process also includes a step of forming the portions of a golf ball cover from the material.
In yet another aspect, the present invention provides a process for forming a golf ball comprising a step of providing a molding assembly including a first mold defining a first hemispherical molding surface and a first mating surface, a second mold defining a second hemispherical molding surface and a second mating surface, and a mandrel having a generally spherical portion sized to fit within the first and second hemispherical molding surfaces and which creates a void between an outer surface of the spherical portion and the first and second hemispherical molding surfaces. The process also includes a step of positioning the mandrel between the first mold and the second mold such that the spherical portion of the mandrel is generally disposed in the first and second hemispherical molding surfaces. The process further includes a step of providing a flowable molding material and introducing the material into the void defined between the outer surface of the spherical portion and the first and second hemispherical molding surfaces. The process also includes a step of forming portions of a golf ball cover from the material. And, the process also includes a step of removing the mandrel from between the first and second molds and positioning a golf ball core or intermediate golf ball assembly between the first and second molding surfaces such that the golf ball core or intermediate is golf ball assembly contacts the formed portions of the golf ball cover. The process further includes a step of molding the golf ball core or intermediate ball assembly to the portions of the golf ball cover to thereby form a golf ball.
The invention accordingly comprises several apparatus compositions, components and steps and the relation of one or more of such apparatus compositions, components and steps with respect to each other. Moreover, the invention is directed to articles possessing the features, properties, and the relation of elements exemplified in the following detailed disclosure.